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Tooth Cusp
A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two cusps, is also known as the bicuspid valve, and the tricuspid valve has three cusps. In humans A cusp is an occlusal or incisal eminence on a tooth. Canine teeth, otherwise known as cuspids, each possess a single cusp, while premolars, otherwise known as bicuspids, possess two each. Molars normally possess either four or five cusps. In certain populations the maxillary molars, especially first molars, will possess a fifth cusp situated on the mesiolingual cusp known as the Cusp of Carabelli. One other variation of the upper first premolar is the 'Uto-Aztecan' upper premolar. It is a bulge on the buccal cusp that is only found in Native American Indians, with highest frequencies of occurrence in Arizona. The name is not a dental ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Sections Of Teeth Intl
A cross is a religious symbol consisting of two Intersection (set theory), intersecting Line (geometry), lines, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a saltire in heraldic terminology. The cross shape has been widely officially recognized as an absolute and exclusive religious symbol of Christianity from an early period in that religion's history.''Christianity: an introduction'' by Alister E. McGrath 2006 pages 321-323 Before then, it was used as a religious or cultural symbol throughout Europe, in West Asia, west and south Asia (the latter, in the form of the original Swastika); and in Ancient Egypt, where the Ankh was a hieroglyph that represented "life" and was used in the wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th-century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin and Alfred Russel Wallace proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by changes in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mamelon (dentistry)
A mamelon (from French ''mamelon'', "nipple") is one of three rounded protuberances which are present on the cutting edge of an incisor tooth when it first erupts through the gum. Mamelons' appearance can be smoothed by a dentist if they have not been worn down naturally by biting and eating foods. Mamelons are present on permanent central and lateral incisors. Mamelons are easiest to observe on the maxillary central incisor The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located Commonly used terms of relationship and comparison in dentistry, mesial (closer to the mid ...s, and appear as three small prominences on the incisal edge of the tooth. Mamelons are ordinarily of no clinical importance. Usually, they are worn off early in the life of the tooth. References Parts of tooth {{dentistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occlusion (dentistry)
Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest. Static occlusion refers to contact between teeth when the jaw is closed and stationary, while dynamic occlusion refers to occlusal contacts made when the jaw is moving. The masticatory system also involves the periodontium, the TMJ (and other skeletal components) and the neuromusculature, therefore the tooth contacts should not be looked at in isolation, but in relation to the overall masticatory system. Anatomy of Masticatory System One cannot fully understand occlusion without an in depth understanding of the anatomy including that of the teeth, TMJ, musculature surrounding this and the skeletal components. The Dentition and Surrounding Structures The human dentition consists of 32 permanent teeth and these are distributed between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsupial
Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a relatively undeveloped state and then nurtured within a pouch on their mother's abdomen. Extant marsupials encompass many species, including Kangaroo, kangaroos, Koala, koalas, Opossum, opossums, Phalangeriformes, possums, Tasmanian devil, Tasmanian devils, Wombat, wombats, Wallaby, wallabies, and Bandicoot, bandicoots. Marsupials constitute a clade stemming from the last common ancestor of extant Metatheria, which encompasses all mammals more closely related to marsupials than to Placentalia, placentals. The evolutionary split between placentals and marsupials occurred 125-160 million years ago, in the Middle Jurassic-Early Cretaceous period. Presently, close to 70% of the 334 extant marsupial species are concentrated on the Australian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placental
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished from monotremes and marsupials in that the fetus (biology), fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer, considering that marsupials also nourish their fetuses via a placenta, though for a relatively briefer period, giving birth to less-developed young, which are then nurtured for a period inside the mother's pouch (marsupial), pouch. Placentalia represents the only living group within Eutheria, which contains all mammals that are more closely related to placentals than they are to marsupials. Anatomical features Placental mammals are anatomically distinguished from other mammals by: * a sufficiently wide opening at the bottom of the pelvis to allow the birt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptations
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th-century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin and Alfred Russel Wallace proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by changes in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheek
The cheeks () constitute the area of the face below the eyes and between the nose and the left or right ear. ''Buccal'' means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside of the cheek and the teeth and gums is called the vestibule or ''buccal'' pouch or ''buccal'' cavity and forms part of the mouth. In other animals, the cheeks may also be referred to as " jowls". Structure Cheeks are fleshy in humans, the skin being suspended by the chin and the jaws, and forming the lateral wall of the human mouth, visibly touching the cheekbone below the eye. The inside of the cheek is lined with a mucous membrane (''buccal'' mucosa, part of the oral mucosa). During mastication (chewing), the cheeks and tongue between them serve to keep the food between the teeth. Clinical significance The cheek is the most common location from which a DNA sample can be taken. (Some saliva is collected from inside the mouth, e.g. using a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominids
The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); '' Gorilla'' (the eastern and western gorilla); '' Pan'' (the chimpanzee and the bonobo); and ''Homo'', of which only modern humans (''Homo sapiens'') remain. Numerous revisions in classifying the great apes have caused the use of the term ''hominid'' to change over time. The original meaning of "hominid" referred only to humans (''Homo'') and their closest extinct relatives. However, by the 1990s humans and other apes were considered to be "hominids". The earlier restrictive meaning has now been largely assumed by the term ''hominin'', which comprises all members of the human clade after the split from the chimpanzees (''Pan''). The current meaning of "hominid" includes all the great apes including humans. Usage still varies, however, and some scientis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molars
The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across the mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusp (dentistry), cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a Third molar, wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies among individuals and populations, and in many cases the tooth is missing. The human mouth contains upper (maxillary) and lower (mandibular) molars. They are: max ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cusp (dentistry)
A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two Heart valve#Structure, cusps, is also known as the bicuspid valve, and the tricuspid valve has three cusps. In humans A cusp is an Commonly used terms of relationship and comparison in dentistry, occlusal or Commonly used terms of relationship and comparison in dentistry, incisal eminence on a tooth. canine tooth, Canine teeth, otherwise known as cuspids, each possess a single cusp, while premolars, otherwise known as bicuspids, possess two each. Molars normally possess either four or five cusps. In certain populations the maxillary molars, especially first molars, will possess a fifth cusp situated on the Commonly used terms of relationship and comparison in dentistry, mesiolingual cusp known as the Cusp of Carabelli. One other variat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
